title: Quantification of N-acetyl- and N-glycolylneuraminic acids by a stable isotope dilution assay using high-performance liquid chromatography-tandem mass spectrometry.
abstract: The present report describes a method for the quantification of N-acetyl- and N-glycolylneuraminic acids without any derivatization, using their (13)C(3)-isotopologues as internal standards and a C(18) reversed-phase column modified by decylboronic acid which allows for the first time a complete chromatographic separation between the two analytes. The method is based on high-performance liquid chromatographic coupled with electrospray ion-trap mass spectrometry. The limit of quantification of the method is 0.1mg/L (2.0ng on column) for both analytes. The calibration curves are linear for both sialic acids over the range of 0.1-80mg/L (2.0-1600ng on column) with a correlation coefficient greater than 0.997. The proposed method was applied to the quantitative determination of sialic acids released from fetuin as a model of glycoproteins.
authors.affiliation: Dipartimento di Chimica, Biochimica e Biotecnologie per la Medicina, Università di Milano, via Saldini 50, I-20133 Milan, Italy. pietro.allevi@unimi.it
authors.forename: Pietro
authors.initials: P
authors.lastname: Allevi
authors.forename: Eti Alessandra
authors.initials: EA
authors.lastname: Femia
authors.forename: Maria Letizia
authors.initials: ML
authors.lastname: Costa
authors.forename: Roberta
authors.initials: R
authors.lastname: Cazzola
authors.forename: Mario
authors.initials: M
authors.lastname: Anastasia
mesh_terms: D000818:Animals; D001897:Boronic Acids / Q000737:chemistry; D002138:Calibration; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006868:Hydrolysis; D007554:Isotopes / Q000737:chemistry; D009438:Neuraminic Acids / Q000032:analysis*; D012015:Reference Standards; D012680:Sensitivity and Specificity; D012794:Sialic Acids / Q000032:analysis*; D053719:Tandem Mass Spectrometry / Q000379:methods; D000509:alpha-Fetoproteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001897:Boronic Acids; D007554:Isotopes; D009438:Neuraminic Acids; D012794:Sialic Acids; D000509:alpha-Fetoproteins; C032592:N-glycolylneuraminic acid